This invention relates to a bearing assembly and more particularly to elastomeric journal bearing assemblies which are adapted for use in supporting marine propeller shafts. Elastomeric journal bearings have been found to be particularly suited for this purpose because of their exceptional ability to withstand the effects of corrosive fluids and to abrasion resulting from bits of foreign materials which are carried in suspension in the sea water or other liquids in which the shaft and journal bearing assembly operates. Such elastomeric journal bearing assemblies have been made and are still being made with rigid metallic support members but the materials are more expensive and the manufacturing costs are higher. A further advantage of the elastomeric journal bearings is that since they operate in a liquid medium they are self lubricated and therefore highly desirable for marine use as for the stern propeller shaft journals.
The present invention is directed to a new and improved bearing assembly and the method of making such assembly utilizing a novel combination of shell and replaceable staves wherein the plurality of circumferentially spaced staves with flat bearing members provides support for a rotating shaft. The invention employs a molding process wherein the individual staves have radially outwardly extending projections about which fabric impregnated with plastic is wrapped filling in the recesses between the projections as well as around the projections to make a cylindrical shell. The radial outward portion of the stave including the projection is made from ultra high molecular weight polyethylene such that after curing of the shell, the staves are freely removable since the plastic shell does not adhere or stick to the ultra high molecular weight polyethylene. This process is considerably less expensive than the corresponding use of a machined recess or dovetail groove as in a brass bushing to receive the dovetail projection of the bearing element. With the use of this process it is particularly advantageous to fabricate a bearing assembly wherein adjacent bearing elements have sufficient clearance between them to provide a water course for lubrication purposes while maintaining their precise position relative to adjacent bearing elements or staves. A unique advantage of this invention is that the removeable staves are used in building the rigid housing assuring precise fitting while reducing the cost of fabrication. In this manufacturing process the rigid outer shell can be machined to a precise outer diameter as the job requires thereby reducing inventory. Additional layers of fiberglass reinforced plastic can be molded onto the outer shell to increase the diameter of the outer shell. The bearing assembly is simple in construction and has the attributes of a machined bearing assembly.